Multiplexer with acoustic wave filter including resonators on a plurality of die

ABSTRACT

Aspects of this disclosure relate to a multiplexer that includes an acoustic wave filter including acoustic wave resonators on at least two die with a transmission line electrically connecting the acoustic wave resonators on the two die. The acoustic wave filter can include a plurality of acoustic wave resonators on a first die electrically connected to at least one acoustic wave resonator on a second die via the transmission line. The acoustic wave resonator on the second die can provide a relatively high impedance at a respective passband of one or more other filters of the multiplexer. This can reduce effects of the transmission line of the acoustic wave filter on a respective passband of one or more other filters of the multiplexer.

CROSS REFERENCE TO PRIORITY APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference under 37 CFR § 1.57.This application claims the benefit of priority of U.S. ProvisionalPatent Application No. 62/884,621, filed Aug. 8, 2019 and titled“MULTIPLEXER WITH ACOUSTIC WAVE FILTER INCLUDING RESONATORS ON APLURALITY OF DIE,” and U.S. Provisional Patent Application No.62/884,619, filed Aug. 8, 2019 and titled “MULTIPLEXER INCLUDINGACOUSTIC WAVE FILTER WITH TRANSMISSION LINE BETWEEN RESONATORS,” thedisclosures of each which are hereby incorporated by reference in theirentireties herein.

BACKGROUND Technical Field

Embodiments of this disclosure relate to acoustic wave filters.

Description of Related Technology

An acoustic wave filter can include a plurality of resonators arrangedto filter a radio frequency signal. Example acoustic wave filtersinclude surface acoustic wave (SAW) filters and bulk acoustic wave (BAW)filters. A surface acoustic wave resonator can include an interdigitaltransductor electrode on a piezoelectric substrate. The surface acousticwave resonator can generate a surface acoustic wave on a surface of thepiezoelectric layer on which the interdigital transductor electrode isdisposed. In BAW resonators, acoustic waves propagate in a bulk of apiezoelectric layer. Example BAW resonators include film bulk acousticwave resonators (FBARs) and solidly mounted resonators (SMRs).

Acoustic wave filters can be implemented in radio frequency electronicsystems. For instance, filters in a radio frequency front end of amobile phone can include acoustic wave filters. An acoustic wave filtercan be a band pass filter. A plurality of acoustic wave filters can bearranged as a multiplexer. For example, three acoustic wave filters canbe arranged as a triplexer.

In multiplexers, acoustic wave filters can be implemented by a pluralityof die. Maintaining low insertion loss and a high reflection coefficientfor an acoustic wave filter of a multiplexer that includes a pluralityof die can be difficult to achieve.

SUMMARY

The innovations described in the claims each have several aspects, nosingle one of which is solely responsible for its desirable attributes.Without limiting the scope of the claims, some prominent features ofthis disclosure will now be briefly described.

One aspect of this disclosure is a multiplexer for filtering radiofrequency signals. The multiplexer includes a multi-die acoustic wavefilter and an acoustic wave filter coupled to the multi-die acousticwave filter at a common node. The multi-die acoustic wave filterincludes a first acoustic resonator on a first die and a second acousticresonator on a second die. The first acoustic resonator is electricallyconnected to the second acoustic resonator via a transmission line. Thefirst acoustic resonator is electrically connected to the common nodevia the transmission line. The acoustic wave filter includes a pluralityof series acoustic resonators and a plurality of shunt acousticresonators on the second die.

The multiplexer can further include an additional acoustic wave filtercoupled to the common node. The additional acoustic wave filter caninclude a third acoustic resonator on the second die. The additionalacoustic wave filter can further include a fourth acoustic resonator ona third die. The third acoustic resonator can be coupled to the fourthacoustic resonator via a second transmission line.

The multiplexer can include a switch coupled between the second acousticresonator and the common node. Alternatively, the second acousticresonator can be coupled to the common node without an interveningswitch. The common node can be on the second die.

All acoustic resonators of the acoustic wave filter can be on the seconddie.

The first acoustic resonator can be a series resonator and the secondacoustic resonator can be a shunt resonator. Alternatively, the firstacoustic resonator can be a shunt resonator and the second acousticresonator can be a series resonator.

The multi-die acoustic wave filter can further include a third acousticresonator on the second die, in which the second acoustic resonator isseries resonator and the third acoustic resonator is shunt resonator.

The first acoustic resonator can be a surface acoustic wave resonator.Alternatively, the first acoustic resonator can be a bulk acoustic waveresonator.

The first acoustic resonator and the second acoustic resonator can bethe same type of acoustic resonator. The first acoustic resonator andthe second acoustic resonator can be surface acoustic wave resonators.The first acoustic resonator and the second acoustic resonator can bebulk acoustic wave resonators.

The first acoustic resonator can be coupled to the common node via thesecond acoustic resonator. The second acoustic resonator can be asurface acoustic wave resonator.

Another aspect of this disclosure is a multi-chip module that includes amultiplexer and a radio frequency amplifier die. The multiplexerincludes a first filter and a second filter coupled to the first filterat a common node. The first acoustic wave filter includes a firstacoustic resonator on a first die and a second acoustic resonator on asecond die. The first acoustic resonator is electrically connected tothe second acoustic resonator via a transmission line. The firstacoustic resonator is electrically connected to the common node via thetransmission line. The second filter includes a plurality of seriesacoustic resonators and a plurality of shunt acoustic resonators on thesecond die. The first die and the second die are positioned on asubstrate. The radio frequency amplifier die is positioned on thesubstrate. The radio frequency amplifier die includes a radio frequencyamplifier operatively coupled to the first filter.

The radio frequency amplifier can be a low noise amplifier. The radiofrequency amplifier die can further include a second low noise amplifieroperatively coupled to the second filter. A switch can selectivelycouple the first filter to the low noise amplifier and to selectivelycouple the second filter to the low noise amplifier. The multi-chipmodule can include a power amplifier operatively coupled to the secondfilter.

The radio frequency amplifier can be a power amplifier.

The multiplexer can include one or more additional features of themultiplexer disclosed herein.

Another aspect of this disclosure is a wireless communication devicethat includes a multiplexer, an antenna, a radio frequency amplifier,and a transceiver in communication with the radio frequency amplifier.The multiplexer includes a first filter and a second filter coupled tothe first filter at a common node. The first acoustic wave filterincludes a first acoustic resonator on a first die and a second acousticresonator on a second die. The first acoustic resonator is electricallyconnected to the second acoustic resonator via a transmission line. Thefirst acoustic resonator is electrically connected to the common nodevia the transmission line. The second filter includes a plurality ofseries acoustic resonators and a plurality of shunt acoustic resonatorson the second die. The antenna is operatively coupled to the commonnode. The radio frequency amplifier is operatively coupled to the firstfilter. The radio frequency amplifier is configured to amplify a radiofrequency signal.

The wireless communication device can further include a basebandprocessor in communication with the transceiver. The wirelesscommunication device can further include one or more additional featuresof any of the multiplexers and/or the multi-chip modules disclosedherein.

The multiplexer can be included in a radio frequency front end. Themultiplexer can be included in a diversity receive module.

Another aspect of this disclosure is a method of filtering a radiofrequency signal. The method includes receiving a radio frequency signalat an input port of a first acoustic wave filter of a multiplexer inaccordance with any suitable principles and advantages disclosed herein.The method includes filtering the radio frequency signal with the firstacoustic wave filter.

Another aspect of this disclosure is a multiplexer for filtering radiofrequency signals. The multiplexer includes a multi-die acoustic wavefilter and an acoustic wave filter coupled to the multi-die acousticwave filter at a common node. The multi-die acoustic wave filterincludes a first acoustic resonator on a first die and a second acousticresonator on a second die. The first acoustic resonator is electricallyconnected to the second acoustic resonator via a transmission line. Thefirst acoustic resonator is electrically connected to the common nodevia the transmission line. The acoustic wave filter includes a pluralityof series acoustic resonators and a shunt acoustic resonator on thesecond die.

Another aspect of this disclosure is a multiplexer for filtering radiofrequency signals. The multiplexer includes a multi-die acoustic wavefilter and an acoustic wave filter coupled to the multi-die acousticwave filter at a common node. The multi-die acoustic wave filterincludes a first acoustic resonator on a first die and a second acousticresonator on a second die. The first acoustic resonator is electricallyconnected to the second acoustic resonator via a transmission line. Thefirst acoustic resonator is electrically connected to the common nodevia the transmission line. The acoustic wave filter includes a seriesacoustic resonator and a plurality of shunt acoustic resonators on thesecond die.

Another aspect of this disclosure is a multiplexer for filtering radiofrequency signals. The multiplexer includes a first acoustic wave filterand a second acoustic wave filter. The first acoustic wave filterincludes a first acoustic resonator on a first die and a second acousticresonator on a second die. The second acoustic resonator is electricallyconnected to the first acoustic resonator via a transmission line. Thefirst acoustic resonator is the same type of acoustic resonator as thesecond acoustic resonator. The second acoustic wave filter is coupled tothe first acoustic wave filter at a common node.

The first acoustic resonator and the second acoustic resonator can besurface acoustic wave resonators. Alternatively or additionally, thefirst acoustic resonator and the second acoustic resonator can be bulkacoustic wave resonators.

The second acoustic wave filter can include a third acoustic resonatoron the second die. The second acoustic wave filter can include a fourthacoustic resonator on a third die, in which the third acoustic resonatorcoupled to the fourth acoustic resonator via a second transmission line.The second acoustic resonator and the third acoustic resonator can beelectrically connected to each other on the second die.

The multiplexer can include a switch coupled between the first acousticwave filter and the common node. The switch can also be coupled betweenthe second acoustic wave filter and the common node.

The first acoustic wave filter can be coupled to the common node withoutan intervening switch.

The common node can be on the second die.

The first acoustic resonator and the second acoustic resonator can beseries resonators. Alternatively, the first acoustic resonator and thesecond acoustic resonator can be shunt resonators.

The first acoustic wave filter can further include a third acousticresonator on the second die, in which the second acoustic resonator is aseries resonator, and in which the third acoustic resonator is a shuntresonator.

The multiplexer can further include a third acoustic wave filter coupledto the common node. The second acoustic wave filter can include a thirdacoustic resonator on the second die. The third acoustic wave filter caninclude a fourth acoustic resonator on the second die. All acousticresonators of the third acoustic wave filter can be on the second die.The second acoustic wave filter can include another acoustic resonatoron a third die.

Another aspect of this disclosure is a multiplexer for filtering radiofrequency signals. The multiplexer includes a first acoustic wave filterand a second acoustic wave filter. The first acoustic wave filterincludes a plurality of bulk acoustic wave resonators on a first die anda first surface acoustic wave resonator on a second die. The pluralityof bulk wave resonators is electrically connected to the first surfaceacoustic wave resonator and a common node via a transmission line. Thesecond acoustic wave filter is coupled to the first acoustic wave filterat the common node. The second acoustic wave filter includes a secondsurface acoustic wave resonator on the second die.

The second acoustic wave filter can include another acoustic resonatoron a third die, in which the second surface acoustic wave resonator iscoupled to the another acoustic resonator via a second transmissionline.

The multiplexer can include a switch coupled between the first acousticwave filter and the common node. The switch can also be coupled betweenthe second acoustic wave filter and the common node.

The first acoustic wave filter can be coupled to the common node withoutan intervening switch.

The common node can be on the second die.

The first surface acoustic wave resonator can be a series resonator. Thesecond surface acoustic wave resonator can be a series resonator.

The first surface acoustic wave resonator can be a shunt resonator. Thesecond surface acoustic wave resonator can be a shunt resonator.

The first acoustic wave filter can include another surface acoustic waveresonator on the second die.

The multiplexer can include a third acoustic wave filter coupled to thecommon node. The third acoustic wave filter can include a third surfaceacoustic wave resonator on the second die. The second surface acousticwave resonator and the third surface acoustic wave can be electricallyconnected to each other on the second die. All acoustic resonators ofthe third acoustic wave filter can be on the second die. The secondacoustic wave filter can include another acoustic resonator on a thirddie.

The first surface acoustic wave resonator can be a temperaturecompensated surface acoustic wave resonator. The second surface acousticwave resonator can be a temperature compensated surface acoustic waveresonator.

Another aspect of this disclosure is a multi-chip module that includes amultiplexer in accordance with any suitable principles and advantagesdisclosed herein and a radio frequency amplifier die. The multiplexerincludes a multi-die acoustic wave filter on a substrate. The radiofrequency amplifier die is positioned on the substrate. The radiofrequency amplifier die includes a radio frequency amplifier operativelycoupled to the multi-die acoustic wave filter.

The radio frequency amplifier can be a low noise amplifier. Themulti-chip module can include a switch configured to selectively couplethe multi-die acoustic wave filter to the low noise amplifier.

The radio frequency amplifier can be a power amplifier.

Another aspect of this disclosure is a wireless communication device.The wireless communication device includes a multiplexer, an antennaoperatively coupled to a common node of the multiplexer, a radiofrequency amplifier operatively coupled to a filter of the multiplexer,and a transceiver in communication with the radio frequency amplifier.The multiplexer includes a filter that includes acoustic wave resonatorson a plurality of dies in accordance with any suitable principles andadvantages disclosed herein.

The wireless communication device can include a baseband processor incommunication with the transceiver.

The multiplexer can be included in a radio frequency front end. Themultiplexer can be included in a diversity receive module.

For purposes of summarizing the disclosure, certain aspects, advantagesand novel features of the innovations have been described herein. It isto be understood that not necessarily all such advantages may beachieved in accordance with any particular embodiment. Thus, theinnovations may be embodied or carried out in a manner that achieves oroptimizes one advantage or group of advantages as taught herein withoutnecessarily achieving other advantages as may be taught or suggestedherein.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of this disclosure will now be described, by way ofnon-limiting example, with reference to the accompanying drawings.

FIG. 1 is a schematic block diagram of a multiplexer.

FIG. 2A is a Smith chart of a standalone filter of the multiplexer ofFIG. 1 without a transmission line as the ideal case.

FIG. 2B is a Smith chart of a standalone filter of the multiplexer ofFIG. 1 that illustrates rotated phase and degraded reflectioncoefficient due to a transmission line.

FIG. 3 is a schematic diagram that includes a filter of a multiplexeraccording to an embodiment.

FIG. 4 is a schematic diagram that includes a filter of a multiplexerwithout a transmission line as the ideal case.

FIG. 5 is a schematic diagram that includes a filter of a multiplexerwith a transmission line with a time delay and resistance.

FIG. 6A is a graph of a reflection coefficient for the filters of FIGS.3, 4, and 5.

FIG. 6B is a graph of a phase shift for the filters of FIGS. 3, 4, and5.

FIG. 7 is schematic diagram of a multi-chip module that includes amultiplexer with an acoustic wave filter having resonators on aplurality of die according to an embodiment.

FIG. 8A is a schematic diagram of example radio frequency amplifiers ofthe multi-chip module of FIG. 7.

FIG. 8B is a schematic diagram of example radio frequency amplifiers ofthe multi-chip module of FIG. 7.

FIG. 8C is another schematic diagram of example radio frequencyamplifiers of the multi-chip module of FIG. 7.

FIG. 9 is schematic diagram of a multi-chip module that includes amultiplexer with an acoustic wave filter having resonators on aplurality of die according to an embodiment.

FIG. 10 is schematic diagram of a multi-chip module that includes amultiplexer with acoustic wave filters each having resonators on aplurality of die according to an embodiment.

FIG. 11 is schematic diagram of a multi-chip module that includes amultiplexer with two acoustic wave filters electrically connected toeach other on a die that includes at least one resonator of each of thetwo acoustic filters according to an embodiment.

FIG. 12 is schematic diagram of a multi-chip module that includes amultiplexer with an acoustic wave filter having a series resonator and ashunt resonator on each of a plurality of die according to anembodiment.

FIG. 13 is schematic diagram of a multi-chip module that includes amultiplexer with a plurality of acoustic wave filters each having ashunt resonator electrically connected to other acoustic wave resonatorsof a respective filter on another die via a respective transmission lineaccording to an embodiment.

FIG. 14 is schematic diagram of a multi-chip module that includes lownoise amplifiers, a power amplifier, and a multiplexer with an acousticwave filter having resonators on a plurality of die according to anembodiment.

FIG. 15 is schematic diagram of a multi-chip module that includes amultiplexer directly electrically connected to an antenna according toan embodiment.

FIG. 16 is schematic diagram of a multi-chip module that includes amultiplexer with one acoustic wave filter having resonators on aplurality of die according to an embodiment.

FIG. 17 is schematic diagram of a multi-chip module that includes amultiplexer with an acoustic wave filter having resonators on two dieand two other acoustic wave filters having resonators on one of the twodie according to an embodiment.

FIG. 18 is schematic diagram of a multi-chip module that includes amultiplexer with an acoustic wave filter having resonators on two dieand two other acoustic wave filters having resonators on one of the twodie according to another embodiment.

FIG. 19 is schematic diagram of a multi-chip module that includes a diewith acoustic resonators of filters of different multiplexers accordingto an embodiment.

FIG. 20 is schematic diagram of a multiplexer with filters electricallyconnected to a common node without an intervening switch according to anembodiment.

FIG. 21 is schematic diagram of a multiplexer with filters electricallyconnected to a common node via a switch according to an embodiment.

FIG. 22 is schematic diagram of a plurality of multiplexers electricallyconnected to an antenna node via a switch according to an embodiment.

FIG. 23 is a schematic block diagram of a wireless communication devicethat includes a multiplexer according to an embodiment.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

The following description of certain embodiments presents variousdescriptions of specific embodiments. However, the innovations describedherein can be embodied in a multitude of different ways, for example, asdefined and covered by the claims. In this description, reference ismade to the drawings where like reference numerals can indicateidentical or functionally similar elements. It will be understood thatelements illustrated in the figures are not necessarily drawn to scale.Moreover, it will be understood that certain embodiments can includemore elements than illustrated in a drawing and/or a subset of theelements illustrated in a drawing. Further, some embodiments canincorporate any suitable combination of features from two or moredrawings.

A multiplexer can include a plurality of acoustic wave filtersimplemented on a plurality of die. When each acoustic wave filter isimplemented on a separate die, a transmission line exists betweenacoustic resonators of an acoustic wave filter and a common node of themultiplexer. The transmission line can lead to insertion lossdegradation due to worse impedance matching and reflection coefficient(gamma).

To reduce impedance mismatches resulting from a transmission linebetween acoustic resonators of a filter and a common node of amultiplexer, a circuit including an inductor and a capacitor can bearranged to provide phase rotation. However, both insertion loss andgamma of the acoustic wave filter can be degraded due to finite qualityfactor (Q) of the inductor and capacitor circuit arranged to providephase rotation. In addition, module size and cost can be increased bythe inductor and capacitor circuit.

Aspects of this disclosure relate to a multiplexer that includes anacoustic wave filter including acoustic wave resonators on at least twodie with a transmission line electrically connecting the acoustic waveresonators on the two die. For example, an acoustic wave filter caninclude acoustic wave resonators on a first die electrically connectedto at least one acoustic wave resonator on a second die via atransmission line. In this example, the acoustic wave resonators on thefirst die can be electrically connected to a common node of amultiplexer by way of an acoustic wave resonator on the second die. Theacoustic wave resonator on the second die can provide a high impedanceat a respective passband of one or more other filters of themultiplexer. Accordingly, effects of the transmission line of theacoustic wave filter on a respective passband of one or more otherfilters of the multiplexer can be reduced and/or eliminated.

Multiplexers disclosed herein can achieve lower insertion loss.Multiplexers disclosed herein can also be implemented in a module withreduced size relative to a module with a phase rotation circuit (e.g.,an inductor and capacitor circuit) arranged to improve impedancematching for an acoustic wave filter.

Multiplexers disclosed herein can include one or more filters arrangedto filter a radio frequency signal in a fifth generation (5G) New Radio(NR) operating band within Frequency Range 1 (FR1). FR1 can from 410megahertz (MHz) to 7.125 gigahertz (GHz), for example, as specified in acurrent 5G NR specification. A filter arranged to filter a radiofrequency signal in a 5G NR FR1 operating band can be an acoustic wavefilter that includes acoustic resonators on a plurality of different diein accordance with any suitable principles and advantages disclosedherein. A filter arranged to filter a radio frequency signal in fourthgeneration (4G) Long Term Evolution (LTE) operating band can be anacoustic wave filter that includes acoustic resonators on a plurality ofdifferent die in accordance with any suitable principles and advantagesdisclosed herein. In some instances, a multi-die acoustic wave filtercan be arranged to have a passband that spans a 5G NR FR1 operating bandand also a 4G LTE operating band. Multiplexers disclosed herein can beimplanted in dual connectivity applications.

Acoustic wave filters arranged to filter signals within a 5G NRoperating band can have wider bandwidth than acoustic wave filtersarranged to filter only 4G LTE signals. For example, Band n70 is widerthan Band 25. This can present technical challenges. Technical solutionsdisclosed herein can address such technical challenges. Carrieraggregation specifications in 5G can be more difficult to meet thancertain 4G carrier aggregation specifications.

Technical solutions disclosed herein can be implemented in carrieraggregation applications. For example, technical solutions disclosedherein can provide desirable phase and/or impedance rotationcharacteristics for an acoustic wave filter. This can increase arefection coefficient of one filter of a multiplexer in a passband ofanother filter of the multiplexer.

Multi-die acoustic wave filters disclosed herein can achieve arelatively wide passband and a relatively high electromechanicalcoupling coefficient (k²). Such filters can also achieve a passband withrelatively sharp edges. In a filter with acoustic resonators on aplurality of different die, stacks of acoustic resonators on differentfilters can be separately adjusted. The electromechanical couplingcoefficient can be increased, for example, by adjusting an acousticresonator stack on a die closest to the common node of a multiplexer.For instance, the acoustic wave filter can include bulk acoustic waveresonators on a first die electrically connected to one or moretemperature compensated surface acoustic wave resonators on a second dievia a transmission line. The one or more temperature compensated surfaceacoustic wave resonators can include a front end resonator closest tothe common node of a multiplexer. The bulk acoustic wave resonators ofthe multi-die acoustic wave filter can encounter difficulties inmaintaining relatively high electromechanical coupling coefficient andquality factor (Q) over a relatively wide bandwidth. By adjusting thestack of the temperature compensated surface acoustic wave resonator onthe die closest to the common node of the multiplexer, electromechanicalcoupling coefficient of the multi-die acoustic wave filter can beincreased. At the same time, the BAW resonators can realize a relativelywide passband for the multi-die acoustic wave filter.

FIG. 1 is a schematic block diagram of a multiplexer 10. As illustrated,the multiplexer 10 includes a first filter 12, a second filter 14, afirst transmission line 15, a second transmission line 16, and a radiofrequency switch with switch arms 18A and 18B.

The first filter 12 is electrically coupled between a first radiofrequency input/output port RF_1 and a common node COM of themultiplexer 10. The common node COM can be referred to as a common port.The first radio frequency input/output port RF_1 can be an output ininstances where the first filter 12 is a receive filter. The first radiofrequency input/output port RF_1 can be an input in instances where thefirst filter 12 is a transmit filter. The first filter 12 is coupled tothe radio frequency switch via the first transmission line 15. The firstswitch arm 18A can selectively electrically couple the first filter 12to the common node COM.

The second filter 14 is electrically coupled between a second radiofrequency input/output port RF_2 and the common node COM. The secondradio frequency input/output port RF_2 can be an output in instanceswhere the second filter 14 is a receive filter. The second radiofrequency input/output port RF_2 can be an input in instances where thesecond filter 14 is a transmit filter. The second filter 14 is coupledto the radio frequency switch via the second transmission line 16. Thesecond switch arm 18B can selectively electrically couple the secondfilter 14 to the common node COM. The multiplexer 10 is a duplexer asillustrated.

The first filter 12 can be arranged to be open for a passband of thesecond filter 14. Similarly, the second filter 14 can be arranged to beopen for a passband of the first filter 12. With the filters 12 and 14of the multiplexer 10 arranged to be open at passbands of each other,loading loss can be reduced and/or eliminated.

FIG. 2A is a Smith chart of a standalone filter of the multiplexer ofFIG. 1 without the transmission line 15 as the ideal case. The Smithchart of FIG. 2A corresponds to the first filter 12 in the multiplexer10 of FIG. 1 without the transmission line 15 as the ideal case. ThisSmith chart indicates open impedance for the first filter 12 in thepassband of the second filter 14.

FIG. 2B is a Smith chart of a standalone filter of the multiplexer ofFIG. 1 that illustrates rotated phase and degraded reflectioncoefficient due to a transmission line. The transmission lines 15 and 16illustrated in FIG. 1 can impact insertion loss. The transmission lines15 and 16 each have a respective time delay and resistance. Such timedelays and resistances can result in impedance mismatches and areduction in gamma of the filters 12 and 14 of the multiplexer 10.

The Smith chart of FIG. 2B corresponds to the first filter 12 in themultiplexer 10 of FIG. 1 with the transmission line 15 having a timedelay and resistance. The Smith chart shown in FIG. 2B indicates arotated phase and degraded gamma for the first filter 12 due to impactsof the transmission line 15. The rotated phase and degraded gamma resultin higher insertion loss in the multiplexer 10. For example, FIG. 2Bindicates that the impedance of the first filter 12 in the passband forthe second filter 14 is rotated relative to FIG. 2A. This impedancerotation and gamma degradation for the first filter 12 in the passbandof the second filter 14 can result in a higher insertion loss for thesecond filter 14 in the passband of the second filter 14.

FIG. 3 is a schematic diagram that includes a filter 30 of a multiplexeraccording to an embodiment. As illustrated, the filter 30 includesacoustic resonators 33A, 33B, and 34 on a first die 32 and an acousticresonator 36 external to the first die 32. The acoustic resonator 36 iselectrically connected to the acoustic resonators 33A, 33B, and 34 ofthe first die 32 via a transmission line 35. The transmission lineextends from the first die 32 to another die that includes the acousticresonator 36. A switch 38 is arranged to selectively electricallyconnect the acoustic resonators of the filter 30 to a common node COM ofthe multiplexer. The multiplexer includes one or more additional filters(not shown in FIG. 3) that are arranged to be electrically coupled tothe common node COM.

In the filter 30, the acoustic resonator 36 is coupled between thetransmission line 35 and the common node COM of the multiplexer.Accordingly, a series acoustic resonator 36 is coupled between thetransmission line 35 and the common node COM in the filter 30. Theacoustic resonator 36 can be high impedance at respective passbands ofone or more other filters of the multiplexer. The topology of the filter30 can reduce and/or eliminate effects of the transmission line 35 onpassbands of one or more other filters of the multiplexer.

FIG. 4 is a schematic diagram that includes a filter 40 of a multiplexerwithout a transmission line as the ideal case. The filter 30 includesacoustic resonators 33A, 33B, 34A, and 34B on a single die 42. Theacoustic resonators 33A, 33B, 34A, and 34B are electrically connected tothe switch 38 without a transmission line.

FIG. 5 is a schematic diagram that includes a filter 50 of a multiplexerwith a transmission line 55 with a time delay and resistance. The filter50 is like the filter 40 of FIG. 4 except that the transmission line 55has the time delay and resistance.

FIG. 6A is a graph of a reflection coefficient (gamma) for the filtersof FIGS. 3, 4, and 5. FIG. 6A indicates that gamma is degraded for thefilter 50 of FIG. 5 relative to the filter 30 of FIG. 3 and the filter40 of FIG. 4 in the frequency range shown. FIG. 6A indicates that gammafor the filter 30 is increased relative to the filter 50. The increasein gamma for the filter 30 can be due to including the series acousticresonator 36 between the transmission line 35 and other acousticresonators 33A, 33B, and 34 of the filter 30. Gamma for the filter 30 isrelatively close to the gamma for the filter 40 without a transmissionline as the ideal case.

FIG. 6B is a graph of a phase shift for the filters of FIGS. 3, 4, and5. FIG. 6B indicates that the phase shift for the filter 50 has asignificantly higher magnitude than for the filters 30 and 40. Thefilter 30 can achieve similar phase rotation to the filter 40. FIG. 6Bindicates that the topology of the filter 30 can reduce the magnitude ofphase rotation relative to the filter 50. This can be a result ofreducing effects of the transmission line 35 in the topology of thefilter 30.

Multiplexers can be included in multi-chip modules that include aplurality of die on a common packaging substrate. The plurality of diecan be enclosed by a packaging structure, such as an overmold structure.The multi-chip module can include two or more acoustic resonator diethat include acoustic resonators of filters of a multiplexer. Themulti-chip module can include one or more radio frequency amplifiers.The one or more radio frequency amplifiers can include one or more poweramplifiers and/or one or more low noise amplifiers. The multi-chipmodule can include an antenna switch module.

Example multi-chip modules that include a multiplexer with an acousticwave filter having acoustic wave resonators on at least two die with atransmission line electrically connecting the acoustic wave resonatorson the two die will be discussed with reference to FIGS. 7 and 9 to 19.In these multiplexers, the effects of the transmission line of theacoustic wave filter on respective passbands of one or more otherfilters of the multiplexer can be reduced and/or eliminated. One or moreof the example multi-chip modules can implement a diversity switchingmodule. One or more of the example multi-chip modules can implement amid high band power amplifier module with a multiplexer. Althoughexample embodiments may be discussed with reference to a triplexer forillustrative purposes, any suitable principles and advantages disclosedherein can be applied to other multiplexers, such as duplexers,quadplexers, hexaplexers, and the like. Any suitable principles andadvantages of the multi-chip modules disclosed herein can be implementedtogether with each other.

FIG. 7 is schematic diagram of a multi-chip module 70 that includes amultiplexer with an acoustic wave filter having resonators on aplurality of die according to an embodiment. As illustrated, themulti-chip module 70 includes a first acoustic resonator die 72, asecond acoustic resonator die 74, a third acoustic resonator die 73, anantenna switch module 75, and one or more radio frequency amplifiers 76.The acoustic resonator die 72 to 74, the antenna switch module 75, andthe one or more radio frequency amplifiers 76 are all positioned on apackaging substrate 77. The packaging substrate 77 can be a laminatesubstrate, for example.

The multi-chip module 70 includes a triplexer that includes threeacoustic wave filters coupled to a common node ANT. The illustratedcommon node ANT is an antenna node. The triplexer includes a firstfilter, a second filter, and a third filter. The illustrated filters areacoustic wave filters that each have a ladder topology. The illustratedfilters can each be a band pass filter. One or more filters of themultiplexer can have a different filter topology such as a latticetopology or a hybrid lattice and ladder topology. In some instances, themultiplexer can include a Multi-Mode SAW (MMS) filter, such as adouble-mode SAW (DMS) filter. In some instances, one or more filters ofa multiplexer can include a non-acoustic filter and/or a hybrid acousticwave and inductor-capacitor (LC) filter.

In certain applications, the first, second, and third filters can all bereceive filters. Such applications can include diversity receiveapplications. When the illustrated filters are each receive filters, afirst input/output port I/O₁ can be an input port and a secondinput/output port I/O₂ can be an output port in each respective filter.According to some other applications, the first, second, and thirdfilters can all be transmit filters. When the illustrated filters areeach transmit filters, a first input/output port I/O₁ can be an outputport and a second input/output port I/O₂ can be an input port in eachrespective filter. The first, second, and third filters can include anysuitable combination of one or more transmit filters and/or one or morereceive filters. The triplexer of the multi-chip module 70 can beimplemented in carrier aggregation applications.

As shown in FIG. 7, the second acoustic resonator die 74 includes atleast one acoustic resonator of each of the three filters of thetriplexer. Accordingly, in certain embodiments, all filters of amultiplexer can be electrically connected to common node by way of arespective acoustic resonator on a common die to reduce and/or eliminateeffects of transmission lines between respective filters and common nodeon passbands of one or more other filters. Acoustic wave filtersdiscussed herein may include a certain number of acoustic resonators(e.g., 4) for illustrative purposes. The principles and advantagesdisclosed herein can be applied to filters having any suitable number ofacoustic resonators.

The first filter includes acoustic resonators 83A, 83B, and 84 on thefirst acoustic resonator die 72 electrically connected to acousticresonator 86 on the second acoustic resonator die 74 via a transmissionline 85. The first filter can be referred to as a multi-die acousticwave filter. The first filter can be a band pass filter having abandwidth in a range from about 3% to 7% of a center frequency of thepassband of the first filter. For example, the first filter can be aband pass filter with a bandwidth of at least about 4% of its centerfrequency. The transmission line 85 can have a length in a range from 50micrometers to 2 millimeters, for example. In some instances, thetransmission line 85 can have a length in a range from 100 micrometersto 1 millimeter. The series resonator 86 can have high impedance inpassbands of the second filter and/or the third filter. Accordingly,this can reduce and/or eliminate effects of the transmission line 85 onpassbands of second filter and/or the third filter. In someapplications, the series resonator 86 can be replaced by two resonatorsarranged in anti-series with each other. The two anti-series resonatorsare connected in series with each other with their polarities reversed.In such an application, there is still a series resonator of the firstfilter coupled between acoustic resonators on the first acousticresonator die 72 and the common node of the multiplexer.

The second filter includes acoustic resonators 93A, 93B, and 94 on thethird acoustic resonator die 73 electrically connected to acousticresonator 96 on the second acoustic resonator die 74 via a transmissionline 95. The second filter can be a band pass filter having a bandwidthin a range from about 3% to 7% of a center frequency of the passband ofthe second filter. For example, the second filter can be a band passfilter with a bandwidth of at least about 4% of its center frequency.The transmission line 95 can have a length in a range from 50micrometers to 2 millimeters, for example. In some instances, thetransmission line 95 can have a length in a range from 100 micrometersto 1 millimeter. The series resonator 96 can have high impedance inpassbands of the first filter and/or the third filter.

The third filter includes acoustic resonators 103A, 103B, 104A, and 104Bon the second acoustic resonator die 74. All acoustic resonators of thethird filter can be on the second acoustic resonator die 74. The secondacoustic resonator die 74 includes a plurality of series resonators anda plurality of shunt resonators of the third filter in addition to anacoustic resonator of each of the first and second filters. Although thefirst, second, and third filters shown in FIG. 7 include 4 acousticresonators for illustrative purposes, any suitable number of shuntand/or series resonators can be implemented in a filter of a multiplexerin accordance with any suitable principles and advantages disclosedherein.

The filters of the triplexer shown in FIG. 7 can include surfaceacoustic wave (SAW) resonators, bulk acoustic wave (BAW) resonators, orany suitable combination of SAW and BAW resonators. As an example, eachof the illustrated acoustic resonator die 72, 73, and 74 can include SAWresonators or BAW resonators. The SAW resonators can include temperaturecompensated SAW (TCSAW) resonators in certain instances. A TCSAWresonator typically includes a temperature compensation layer, such as asilicon dioxide layer, over an interdigital transducer electrode tobring a temperature coefficient of frequency (TCF) closer to zero. Insome other applications, one or more of the illustrated die can includea Lamb wave resonator and/or a boundary acoustic wave resonator.

In certain applications, the first acoustic resonator die 72 and/or thethird acoustic resonator die 73 can include a different type of acousticresonator than the second acoustic resonator die 74. For example, thefirst acoustic resonator die 72 can be a BAW die and the second acousticresonator die 74 can be a SAW die. In some such instances, the secondacoustic resonator die 74 can be a TCSAW die.

In some applications, the first acoustic resonator die 72 and/or thethird acoustic resonator die 73 can include acoustic resonators of thesame type as the second acoustic resonator die 74. For instance, thefirst acoustic resonator die 72 can be a SAW die and the second acousticresonator die 74 can be a SAW die. As another example, the firstacoustic resonator die 72 can be a BAW die and the second acousticresonator die 74 can be a BAW die.

Non acoustic passive components, such as surface mount technology (SMT)components (not illustrated in FIG. 7), can be coupled to aninput/output ports of one or more of the illustrated filters.

The first, second, and third filters of the triplexer illustrated inFIG. 7 are each coupled to the common node ANT by way of the antennaswitch module 75. Each filter is coupled to a respective throw of amulti-throw switch of the antenna switch module 75. The multi-throwswitch can selectively electrically connect one or more of the filtersof the triplexer to the common node ANT. The multi-throw switch of theantenna switch module 75 can implement switched multiplexing. In someother embodiments, such as the embodiments shown in FIGS. 9, 12, and 15,a multiplexer can be implemented without a switch coupled between anyfilters of the triplexer and the common node ANT. Such an arrangementcan be referred to as fixed multiplexing.

The one or more radio frequency amplifiers 76 can be coupled to each ofthe filters of the triplexer. The one or more radio frequency amplifiers76 can include one or more low noise amplifiers and/or one or more poweramplifiers. The one or more radio frequency amplifiers 76 can includetwo or more radio frequency amplifiers. In certain applications, the oneor more radio frequency amplifiers 76 can be implemented on one or moreradio frequency amplifier dies. Examples of the one or more radiofrequency amplifiers 76 will be discussed with reference to FIGS. 8A to8C.

FIG. 8A is a schematic diagram of example radio frequency amplifiers 110of a multi-chip module, such as the multi-chip module 70 of FIG. 7. Theradio frequency amplifiers 110 are an example of the one or more radiofrequency amplifiers 76 of FIG. 7 that includes a separate low noiseamplifier operatively coupled to each filter of a multiplexer. Asillustrated, the radio frequency amplifiers 110 include a first lownoise amplifier 112A, a second low noise amplifier 112B, and a third lownoise amplifier 112C. These low noise amplifiers can each beelectrically coupled to a different receive filter in a multiplexer inaccordance with any suitable principles and advantages disclosed herein.

FIG. 8B is a schematic diagram of example radio frequency amplifiers ofa multi-chip module, such as the multi-chip module 70 of FIG. 7. A radiofrequency amplification circuit 114 of FIG. 7 includes an example of theone or more radio frequency amplifiers 76 of FIG. 7. The radio frequencyamplification circuit 114 includes low noise amplifiers 112A and 112Band a radio frequency switch 115. The radio frequency switch 115 canselectively electrically connect the low noise amplifier 112A to aselected one of the filters of the triplexer of FIG. 7. The radiofrequency switch 115 can electrically connect one filter to the lownoise amplifier 112A in a first state and electrically connect anotherfilter to the low noise amplifier 112A in a second state. The other lownoise amplifier 112B can be electrically connected to a different filterof the multiplexer.

FIG. 8B illustrates that one or more filters of a multiplexer can beselectively electrically connected to a radio frequency amplifier (e.g.,a low noise amplifier or a power amplifier) via a radio frequencyswitch. In such instances, a radio frequency amplifier can be sharedamong two or more filters of the multiplexer.

FIG. 8C is another schematic diagram of example radio frequencyamplifiers 116 of a multi-chip module, such as the multi-chip module 70of FIG. 7. The radio frequency amplifiers 116 are an example of the oneor more radio frequency amplifiers 76 of FIG. 7 that includes a separateradio amplifiers operatively coupled to respective filters of amultiplexer. As illustrated, the radio frequency amplifiers 116 includea first low noise amplifier 112A, a second low noise amplifier 112B, anda power amplifier 117. Any suitable combination of one or more poweramplifiers and one or more low noise amplifiers can be coupled tofilters of a multiplexer in accordance with any suitable principles andadvantages disclosed herein.

FIG. 9 is schematic diagram of a multi-chip module 130 that includes amultiplexer with an acoustic wave filter having resonators on aplurality of die according to an embodiment. In the multi-chip module130, each filter of the multiplexer is electrically coupled to a commonnode without an intervening switch. The multi-chip module 130 is similarto the multi-chip module 70 of FIG. 7 except that the first second, andthird filters are coupled to each other at a common node on a secondacoustic resonator die 132 in the multi-chip module 130 and themulti-chip module 130 does not include an antenna switch module. Thesecond acoustic resonator die 132 is similar to the second acousticresonator die 74 of FIG. 7 except that the second acoustic resonator die132 includes an input/output contact coupled to the common node of themultiplexer. In contrast, the second acoustic resonator die 74 of FIG. 7includes separate input/output contacts for each filters of thetriplexer of FIG. 7.

FIG. 10 is schematic diagram of a multi-chip module 135 that includes amultiplexer with acoustic wave filters each having resonators on aplurality of die according to an embodiment. FIG. 10 illustrates thatfront end acoustic resonators of different filters of a multiplexer canbe included on a resonator bank die 136. A front end acoustic resonatorcan be an acoustic resonator through which other acoustic resonators ofa filter are coupled to a common node and/or an antenna node. Themulti-chip module 135 includes a first acoustic resonator die 72, aresonator bank die 136, a third acoustic resonator die 73, a fourthacoustic resonator die 137, an antenna switch module 75, and one or moreradio frequency amplifiers 76. The illustrated resonator bank die 136includes an acoustic resonator of each filter of the multiplexer.

Each acoustic resonator die 72, 73, 137, and 136 can be a BAW resonatordie or a SAW resonator die. The resonator bank die 136 can be a SAWresonator die in certain applications. When the resonator bank die 136die is a SAW resonator die, operating frequencies for different SAWresonators can be adjusted by adjusting interdigital transducer (IDT)electrode finger pitch for respective SAW resonators. The resonator bankdie 136 can be a BAW resonator die in some other applications. Theresonator bank die 136 can include acoustic resonators of the same typeas one or more of the other acoustic resonator die 72, 73, 137 incertain instances.

In an embodiment, the resonator bank die 136 can be a TCSAW die and oneor more of the acoustic resonator die 72, 73, and 137 can be BAW die. Atransmit filter with BAW resonators 93A, 93B, 94 on the third acousticresonator die 73 and a TCSAW resonator 142 on the resonator bank die 136can achieve a relatively wide passband and a relatively high k². Withthe acoustic resonator 142 being a TCSAW resonator and the acousticresonators 93A, 93B, and 94 being BAW resonators, non-linearity, such assecond harmonic distortion, associated with the acoustic resonators 93A,93B, and 94 being BAW resonators can be reduced.

In FIG. 10, the multiplexer includes a first filter, a second filter,and a third filter. The first filter includes acoustic resonators 83A,83B, and 84 on the first acoustic resonator die 72 and an acousticresonator 141 of the resonator bank die 136. The acoustic resonator 141is a series acoustic resonator as illustrated. The acoustic resonator141 can have a high impedance in a passband of the second filter and/orin a passband of the third filter. The acoustic resonator 141 iselectrically connected to the acoustic resonators 83A, 83B, and 84 offirst acoustic resonator die 72 via transmission line 85.

The second filter includes acoustic resonators 93A, 93B, and 94 on thethird acoustic resonator die 73 and an acoustic resonator 142 of theresonator bank die 136. The acoustic resonator 142 is a series acousticresonator as illustrated. The acoustic resonator 142 can have a highimpedance in a passband of the first filter and/or in a passband of thethird filter. The acoustic resonator 142 is electrically connected tothe acoustic resonators 93A, 93B, and 94 of third acoustic resonator die73 via transmission line 95.

In the multi-chip module 135, the third filter includes acousticresonators 103A, 103B, and 104 on the fourth acoustic resonator die 137and an acoustic resonator 143 of the resonator bank die 136. Theacoustic resonator 143 is a series acoustic resonator as illustrated.The acoustic resonator 143 can have a high impedance in a passband ofthe first filter and/or in a passband of the second filter. The acousticresonator 143 is electrically connected to the acoustic resonators 103A,103B, and 104 of the fourth acoustic resonator die 137 via transmissionline 144.

The first filter, second filter, and third filter are coupled to thecommon node ANT by way of the antenna switch module 75 in theillustrated multi-chip module 135. Alternatively, in some otherembodiments (not illustrated), two or more of the acoustic resonators141, 142, and 143 can be coupled to each other on the resonator bank die136. In some such instances, the common node can be on the resonatorbank die 136.

FIG. 11 is schematic diagram of a multi-chip module 145 that includes amultiplexer with two acoustic wave filters electrically connected toeach other on a die that includes at least one resonator of each of thetwo acoustic filters according to an embodiment. FIG. 11 illustratesthat front end resonators can be connected on an acoustic resonator die.The multi-chip module 145 is like the multi-chip module 70 of FIG. 7except that the third acoustic resonator die and antenna switch modulesare different.

In the multi-chip module 145, a second acoustic resonator die 146includes acoustic resonators 86 and 96 of the second and third filters,respectively, that are electrically connected to each other on thesecond acoustic resonator die 146. The acoustic resonators 86 and 96 areelectrically connected to a common input/output contact of the secondacoustic resonator die 146. The second acoustic resonator die 146 alsoincludes acoustic resonators 103A, 103B, 104A, and 104B of the thirdfilter.

An antenna switch module 147 includes a multi-throw radio frequencyswitch that includes a first throw electrically coupled to both theacoustic resonators 86 and 96 of the first and second filters,respectively, and a second throw electrically connected to the acousticresonator 104B of the third filter. The first and second filters areconnected together on the second acoustic resonator die 146 andelectrically coupled to the common node ANT via the antenna switchmodule 147. The third filter is also electrically coupled to the commonnode ANT via the antenna switch module 147.

FIG. 12 is schematic diagram of a multi-chip module 148 that includes amultiplexer with an acoustic wave filter having a series resonator and ashunt resonator on each of a plurality of die according to anembodiment. FIG. 12 illustrates that acoustic resonators on a first diecan be electrically connected to a series acoustic resonator and a shuntacoustic resonator on another die via a transmission line, in which theseries acoustic resonator and the second acoustic resonator are coupledto a node between the acoustic resonators on the first die and a commonnode of a multiplexer that includes the filter.

In the multi-chip module 148, a second acoustic resonator die 149includes both a series acoustic resonator 96 and a shunt acousticresonator 97 of the second filter. The series acoustic resonator 96 andthe shunt acoustic resonator 97 are electrically connected to theacoustic resonators 93 and 94 of the second filter that are on a thirdacoustic resonator die 150 via transmission line 95. The first, second,and third filters of the multiplexer of the multi-chip module 148 areelectrically connected to each other on the second acoustic resonatordie 149. Accordingly, the common node of the multiplexer can be on thesecond acoustic resonator die 149. The common node can be electricallyconnected to an antenna switch module 151. The antenna switch module 151can selectively electrically connect the common node of the multiplexerto an antenna port of the multi-chip module 148.

In some embodiments (not illustrated), the first filter can also includea series acoustic resonator and a shunt acoustic resonator on a seconddie. Accordingly, two or more filters of a multiplexer can each includea series resonator and a shunt resonator on a common acoustic resonatordie that are electrically connected to respective other acousticresonators on a different acoustic resonator die via a transmissionline. In such embodiments, a multiplexer can include a plurality ofacoustic wave filters each having a series resonator and a shuntresonator on each of a plurality of die.

FIG. 13 is schematic diagram of a multi-chip module 152 that includes amultiplexer with a plurality of acoustic wave filters each having ashunt resonator electrically connected to other acoustic wave resonatorsof a respective filter on another die via a respective transmission lineaccording to an embodiment. As shown in FIG. 13, the filter topology maystart with a shunt resonator closest to the common node. In suchinstances, a shunt resonator of an acoustic filter can be electricallyconnected to other acoustic resonators of the acoustic filter that areon another die via a transmission line.

In the multi-chip module 152, a second acoustic resonator die 154includes shunt acoustic resonators 87 and 97 of the first and secondfilters, respectively. The shunt acoustic resonator 87 can provide ahigh impedance in a passband of the second filter and/or a passband ofthe third filter of the multiplexer. The shunt acoustic resonator 87 ofthe first filter is electrically connected to acoustic resonators 83 and84 of the first filter on the first acoustic resonator die 72 viatransmission line 85 in FIG. 13. The illustrated second acousticresonator die 154 also includes a series acoustic resonator 96 of thesecond filter. In FIG. 13, the series acoustic resonator 96 and theshunt acoustic resonator 97 of the second filter are electricallyconnected to the acoustic resonators 93 and 94 of the second filter onthe third acoustic resonator die 150 via transmission line 95. Thefirst, second, and third filters of the multiplexer are electricallyconnected to each other on the second acoustic resonator die 154.

FIG. 14 is schematic diagram of a multi-chip module 155 that includes afirst low noise amplifier 156, a power amplifier 157, a second low noiseamplifier 158, and a multiplexer with an acoustic wave filter havingresonators on a plurality of die according to an embodiment. Themulti-chip module 155 is an example of the multi-chip module 70 of FIG.7 in which the one or more radio frequency amplifiers 76 include the lownoise amplifiers 156 and 158 and the power amplifier 157. FIG. 14illustrates that one filter of a multiplexer can be a transmit filterelectrically coupled to the power amplifier 157 and other filters of themultiplexer can be receive filters electrically coupled to respectivelow noise amplifiers 156 and 158. When a multiplexer includes one ormore transmit filters and one or more receive filters, at least onepower amplifier and at least one low noise amplifier can be electricallyconnected to filters of the multiplexer. One or more radio frequencyamplifiers can be electrically coupled to any suitable combination oftransmit and/or receive filters. Multiplexers in accordance with anysuitable principles and advantages disclosed herein can include anysuitable number of transmit filters and/or receive filters.

FIG. 15 is schematic diagram of a multi-chip module 159 that includes amultiplexer directly electrically connected to an antenna 160 accordingto an embodiment. As shown in FIG. 15, a multiplexer can be electricallyconnected to the antenna 160 without an intervening switch. The antenna160 can be integrated in the multi-chip module 159 in certainapplications. The antenna 160 can be external to the multi-chip module159 in some other applications.

FIG. 16 is schematic diagram of a multi-chip module 162 that includes amultiplexer with one acoustic wave filter having resonators on aplurality of die according to an embodiment. A subset of filters of amultiplexer can include front end resonators on a common acousticresonator die. For example, in the multi-chip module 162, a secondfilter and a third filter of a multiplexer can each include one or moreacoustic resonators on a second acoustic resonator die 165. One or morefilters of a multiplexer can include acoustic resonators on a single diethat does not include an acoustic resonator of another filter of themultiplexer. For example, in the multi-chip module 162, a first filterof a multiplexer include acoustic resonators 83A, 83B, 84A, and 84B on afirst acoustic resonator die 164. The second and third filters of themultiplexer of the multi-chip module 162 do not include an acousticresonator on the first acoustic resonator die 164. The second filterincludes acoustic resonators 93A, 93B, and 94 on the third acousticresonator die 73 and acoustic resonator 96 on the second resonator die165. The acoustic resonator 96 is electrically connected to the otheracoustic resonators 93A, 93B, and 94 of the second filter viatransmission line 95. The first filter and the second filter can beelectrically connected to each other external to the first acousticresonator die 164 and second resonator die 165 and both electricallyconnected to the same port of the antenna switch module 147.

FIG. 17 is schematic diagram of a multi-chip module 170 that includes amultiplexer with an acoustic wave filter having resonators on two dieand two other acoustic wave filters having resonators on one of the twodie according to an embodiment. A plurality of filters can beimplemented on a common acoustic resonator die. The common acousticresonator die can also include a front end acoustic resonator of anotherfilter. For example, in the multi-chip module 170, a first filter of amultiplexer can include a front end acoustic resonator 96 on an acousticresonator die 172 and two other filters of the multiplexer can eachinclude a plurality of acoustic resonators on the acoustic resonator die172. One of the two other filters can include acoustic resonators 103A,103B, 104A, and 104B on the acoustic resonator die 172. The other of thetwo other filters can include acoustic resonators 173A, 173B, 174A, and174B on the acoustic resonator die 172. As illustrated in FIG. 17, allacoustic resonators of each of the two other filters can be on theacoustic resonator die 172.

The multiplexer of the multi-chip mode 170 is coupled to an antenna portof the multi-chip module 170 by way of an antenna switch module 75. Insome other embodiments, the multiplexer can be electrically connected toan antenna port without an intervening switch.

In certain instances, the acoustic resonator die 172 can be a SAW dieand the acoustic resonator die 73 can be a BAW die. In some suchinstances, the acoustic resonator die 172 can be a TCSAW die. A filterwith acoustic resonators on the acoustic resonators on the acousticresonator die 73 and a TCSAW resonator on the acoustic resonator die 172can implement an acoustic filter with advantages of a BAW filter andreduced non-linear distortion from the front end TCSAW resonator.

As illustrated, the multi-die filter that includes acoustic resonators93A, 93B, 94, and 96 is a transmit filter arranged to filter a radiofrequency signal generated by the power amplifier 157.

FIG. 18 is schematic diagram of a multi-chip module 180 that includes amultiplexer with an acoustic wave filter having resonators on two dieand two other acoustic wave filters having resonators on one of the twodie according to another embodiment. The multi-chip module 180 is likethe multi-chip module 170 of FIG. 17, except that all of the illustratedfilers of a multiplexer of the multi-chip module 180 are receive filtersand a low noise amplifier 186 is included in place of the poweramplifier 157. In the multi-chip module 180, the multi-die filter thatincludes the acoustic resonators 93A, 93B, 94, and 96 is a receivefilter. Any suitable principles and advantages disclosed herein can beimplemented in connection with receive filters and/or transmit filters.

FIG. 19 is schematic diagram of a multi-chip module 190 that includes adie with acoustic resonators of filters of different multiplexersaccording to an embodiment. Acoustic resonators from filters ofdifferent multiplexers can be implemented on a common acoustic resonatordie. The common acoustic resonator die can include acoustic resonatorsfrom filters of two or more different multiplexers. Any suitableprinciples and advantages of the other embodiments disclosed herein canbe implemented in association with an acoustic resonator die thatincludes acoustic resonators of filters of two or more multiplexers.

The first multiplexer can be as described with reference to FIGS. 17and/or 18. The multi-chip module 190 includes two additional acousticresonator die 204 and 206 for filters of the second multiplexer. Thesecond multiplexer includes three filters in the multi-chip module 190.The principles and advantages of the second multiplexer of FIG. 19 canbe applied to any suitable multiplexer with a different number offilters. As illustrated in FIG. 19, an acoustic resonator die 202 of themulti-chip module 190 includes acoustic resonators of a firstmultiplexer and a second multiplexer. The acoustic resonator die 202 caninclude a front end resonator of each filter of the second multiplexeras illustrated. In FIG. 19, the acoustic resonator die 202 also includesa front end resonator of each filter of the first multiplexer.

A first filter of the second multiplexer includes acoustic resonators213A, 213B, 214 on the acoustic resonator die 204, an acoustic resonator216 on the acoustic resonator die 202, and a transmission line 215electrically connecting the acoustic resonator 216 and the acousticresonators 213A, 213B, and 214. The first filter can be a receive filterconfigured to provide a filtered radio frequency signal to the low noiseamplifier 246. The low noise amplifier 246 can be implemented on thesame die or a different die than one or more of the other low noiseamplifiers of the multi-chip module 190.

A second filter of the second multiplexer includes acoustic resonators223A, 223B, 224 on the acoustic resonator die 206, an acoustic resonator226 on the acoustic resonator die 202, and a transmission line 225electrically connecting the acoustic resonator 226 and the acousticresonators 223A, 223B, and 224. The second filter can be a transmitfilter configured to filter a radio frequency signal generated by apower amplifier 247. The power amplifier 247 can be implemented ondifferent die than the low noise amplifiers of the multi-chip module190.

The third filter of the second multiplexer includes acoustic resonators233A, 233B, 234A, and 234B. All acoustic resonators of the third filtercan be on the acoustic resonator die 202 as illustrated. The thirdfilter can be a receive filter configured to provide a filtered radiofrequency signal to the low noise amplifier 248. The low noise amplifier248 can be implemented on the same die or a different die than one ormore of the other low noise amplifiers of the multi-chip module 190.

The acoustic resonator die 202 includes input/output ports for thesecond multiplexer. A fourth input/output port I/O₄ port can be a portfor electrically connecting a common node of the second multiplexer tothe antenna switch module 75. A fifth input/output port I/O₅ port can bean output port for electrically connecting to the third filter of thesecond multiplexer to the low noise amplifier 248.

The antenna switch module 75 can selectively electrically connect one ormore of the first multiplexer, the second multiplexer, and/or anothersignal path to an antenna port of the multi-chip module 190.

FIG. 20 is schematic diagram of a multiplexer 250 with filters 252 and254 electrically connected to a common node COM without an interveningswitch according to an embodiment. The multiplexer 250 includes two ormore filters coupled to each other at the common node COM. Any suitablenumber of filters that is two or more can be implemented in themultiplexer 250. Any suitable principles and advantages disclosed hereincan be implemented in a multiplexer without a switch coupled between oneor more filters of the multiplexer and the common node.

FIG. 21 is schematic diagram of a multiplexer 260 with filters 252 and254 electrically connected to a common node COM via a switch 262according to an embodiment. The switch 262 can selectively electricallyconnect one or more filters of the multiplexer 260 to the common nodeCOM. In some instances, the switch 262 can selectively electricallyconnected two or more filters to the common node COM in certain states.Any suitable number of filters that is two or more can be implemented inthe multiplexer 260. Any suitable principles and advantages disclosedherein can be implemented in a multiplexer with a switch coupled betweenone or more filters of the multiplexer and the common node.

FIG. 22 is schematic diagram of a radio frequency system 265 with aplurality of multiplexers 250A to 250M electrically connected to anantenna node via a switch 262 according to an embodiment. Eachmultiplexer 250A to 250M includes two or more filters coupled to eachother at the common node COM. The multiplexer 250A includes filters 252Aand 254A. The multiplexer 250N includes filters 252N and 254N. Anysuitable number of filters that is two or more can be implemented ineach multiplexer. A multiplexer of the radio frequency system 265 caninclude the same or a different number of filters than one or more othermultiplexers of the radio frequency system 265. The switch 262 canselectively electrically connect one or more filters of the multiplexers250A to 250M to an antenna node ANT. Any suitable principles andadvantages disclosed herein can be implemented in one or more of themultiplexers 250A to 250M. Any suitable principles and advantagesassociated with the multi-chip module 190 of FIG. 19 can be implementedfor two or more of the multiplexers 250A to 250M.

The multiplexers disclosed herein can be implemented in a variety ofwireless communication devices. FIG. 23 is a schematic diagram of awireless communication 270 device that includes a multiplexer 273 in aradio frequency front end 272 and a multiplexer 283 in a diversityreceive module 282 according to an embodiment. The multiplexer 273and/or the multiplexer 283 can be implemented in accordance with anysuitable principles and advantages disclosed herein. The wirelesscommunication device 270 can be any suitable wireless communicationdevice. For instance, a wireless communication device 270 can be amobile phone, such as a smart phone. As illustrated, the wirelesscommunication device 270 includes a primary antenna 271, an RF front end272, a transceiver 274, a processor 275, a memory 276, a user interface277, a diversity antenna 281, and a diversity receive module 282.

The antenna 271 can transmit RF signals provided by the RF front end272. Such RF signals can include carrier aggregation signals. Theantenna 271 can receive RF signals and provide the received RF signalsto the RF front end 272 for processing. Such RF signals can includecarrier aggregation signals. The wireless communication device 270 caninclude any suitable number of antennas.

The RF front end 272 can include one or more power amplifiers, one ormore low noise amplifiers, one or more RF switches, one or more receivefilters, one or more transmit filters, one or more duplex filters, oneor more multiplexers, one or more frequency multiplexing circuits, thelike, or any suitable combination thereof. The RF front end 272 cantransmit and receive RF signals associated with any suitablecommunication standards. The multiplexer 273 can include an acousticwave filter with a transmission line between acoustic resonators on aplurality of different die, in which the multiplexer 273 includes anysuitable combination of features of the embodiments disclosed above.

The transceiver 274 can provide RF signals to the RF front end 272 foramplification and/or other processing. The transceiver 274 can alsoprocess an RF signal provided by a low noise amplifier of the RF frontend 272. The transceiver 274 is in communication with the processor 275.The processor 275 can be a baseband processor. The processor 275 canprovide any suitable base band processing functions for the wirelesscommunication device 270. The memory 276 can be accessed by theprocessor 275. The memory 276 can store any suitable data for thewireless communication device 270. The user interface 277 can be anysuitable user interface, such as a display with touch screencapabilities.

The diversity module 282 is configured to process signals received bythe diversity antenna 281. The transceiver 274 is in communication withboth the radio frequency front end 272 and the diversity receive module282. The multiplexer 283 can include any suitable combination offeatures of the multiplexers disclosed herein.

Any of the embodiments described above can be implemented in associationwith mobile devices such as cellular handsets. The principles andadvantages of the embodiments can be used for any systems or apparatus,such as any uplink wireless communication device, that could benefitfrom any of the embodiments described herein. The teachings herein areapplicable to a variety of systems. Although this disclosure includesexample embodiments, the teachings described herein can be applied to avariety of structures. Any of the principles and advantages discussedherein can be implemented in association with RF circuits configured toprocess signals having a frequency in a range from about 30 kHz to 300GHz, such as in a frequency range from about 400 MHz to 8.5 GHz.Acoustic wave filters disclosed herein can filter RF signals in fifthgeneration (5G) New Radio (NR) operating bands within Frequency Range 1(FR1). FR1 can be from 410 MHz to 7.125 GHz, for example.

Aspects of this disclosure can be implemented in various electronicdevices. Examples of the electronic devices can include, but are notlimited to, consumer electronic products, parts of the consumerelectronic products such as packaged radio frequency modules, radiofrequency filter die, uplink wireless communication devices, wirelesscommunication infrastructure, electronic test equipment, etc. Examplesof the electronic devices can include, but are not limited to, a mobilephone such as a smart phone, a wearable computing device such as a smartwatch or an ear piece, a telephone, a television, a computer monitor, acomputer, a modem, a hand-held computer, a laptop computer, a tabletcomputer, a microwave, a refrigerator, a vehicular electronics systemsuch as an automotive electronics system, a robot such as an industrialrobot, an Internet of things device, a stereo system, a digital musicplayer, a radio, a camera such as a digital camera, a portable memorychip, a home appliance such as a washer or a dryer, a peripheral device,a wrist watch, a clock, etc. Further, the electronic devices can includeunfinished products.

Unless the context indicates otherwise, throughout the description andthe claims, the words “comprise,” “comprising,” “include,” “including”and the like are to generally be construed in an inclusive sense, asopposed to an exclusive or exhaustive sense; that is to say, in thesense of “including, but not limited to.” Conditional language usedherein, such as, among others, “can,” “could,” “might,” “may,” “e.g.,”“for example,” “such as” and the like, unless specifically statedotherwise, or otherwise understood within the context as used, isgenerally intended to convey that certain embodiments include, whileother embodiments do not include, certain features, elements and/orstates. The word “coupled”, as generally used herein, refers to two ormore elements that may be either directly connected, or connected by wayof one or more intermediate elements. Likewise, the word “connected”, asgenerally used herein, refers to two or more elements that may be eitherdirectly connected, or connected by way of one or more intermediateelements. Additionally, the words “herein,” “above,” “below,” and wordsof similar import, when used in this application, shall refer to thisapplication as a whole and not to any particular portions of thisapplication. Where the context permits, words in the above DetailedDescription using the singular or plural number may also include theplural or singular number respectively.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the disclosure. Indeed, the novel resonators, filters,multiplexer, devices, modules, wireless communication devices,apparatus, methods, and systems described herein may be embodied in avariety of other forms. Furthermore, various omissions, substitutionsand changes in the form of the resonators, filters, multiplexer,devices, modules, wireless communication devices, apparatus, methods,and systems described herein may be made without departing from thespirit of the disclosure. For example, while blocks are presented in agiven arrangement, alternative embodiments may perform similarfunctionalities with different components and/or circuit topologies, andsome blocks may be deleted, moved, added, subdivided, combined, and/ormodified. Each of these blocks may be implemented in a variety ofdifferent ways. Any suitable combination of the elements and/or acts ofthe various embodiments described above can be combined to providefurther embodiments. The accompanying claims and their equivalents areintended to cover such forms or modifications as would fall within thescope and spirit of the disclosure.

What is claimed is:
 1. A multiplexer for filtering radio frequencysignals, the multiplexer comprising: a first acoustic wave filterincluding a first acoustic resonator on a first die and a secondacoustic resonator on a second die, the first acoustic resonator beingelectrically connected to the second acoustic resonator via atransmission line, the first acoustic wave filter including a singleseries acoustic resonator on the second die, the single series acousticresonator of the first acoustic wave filter on the second die being thesecond acoustic resonator, and the first acoustic resonator beingconnected to a common node via the transmission line and the secondacoustic resonator; and a second acoustic wave filter coupled to thefirst acoustic wave filter at the common node, the second acoustic wavefilter including both a plurality of series acoustic resonators and aplurality of shunt acoustic resonators on the same second die.
 2. Themultiplexer of claim 1 further comprising an additional acoustic wavefilter coupled to the common node, the additional acoustic wave filterincluding a third acoustic resonator on the second die.
 3. Themultiplexer of claim 2 wherein the additional acoustic wave filterfurther includes a fourth acoustic resonator on a third die, the thirdacoustic resonator coupled to the fourth acoustic resonator via a secondtransmission line.
 4. The multiplexer of claim 1 further comprising aswitch coupled between the second acoustic resonator and the commonnode.
 5. The multiplexer of claim 1 wherein the second acousticresonator is coupled to the common node without an intervening switch.6. The multiplexer of claim 1 wherein the common node is on the seconddie.
 7. The multiplexer of claim 1 wherein all acoustic resonators ofthe second acoustic wave filter are on the second die.
 8. Themultiplexer of claim 1 wherein the first acoustic resonator is a seriesresonator.
 9. The multiplexer of claim 1 wherein the first acousticresonator is a shunt resonator.
 10. The multiplexer of claim 1 whereinthe first acoustic wave filter further includes a third acousticresonator on the second die, and the third acoustic resonator is shuntresonator.
 11. The multiplexer of claim 1 wherein the first acousticresonator is a surface acoustic wave resonator.
 12. The multiplexer ofclaim 1 wherein the first acoustic resonator is a bulk acoustic waveresonator.
 13. The multiplexer of claim 1 wherein the first acousticresonator and the second acoustic resonator are the same type ofacoustic resonator.
 14. The multiplexer of claim 1 wherein the firstacoustic resonator and the second acoustic resonator are surfaceacoustic wave resonators.
 15. The multiplexer of claim 1 wherein thefirst acoustic resonator and the second acoustic resonator are bulkacoustic wave resonators.
 16. The multiplexer of claim 1 wherein thesecond acoustic resonator is a surface acoustic wave resonator.
 17. Amulti-chip module comprising: a multiplexer including a first filter anda second filter coupled to the first filter at a common node, the firstfilter including a first acoustic resonator on a first die and a secondacoustic resonator on a second die, the first acoustic resonator beingelectrically connected to the second acoustic resonator via atransmission line, the first filter including a single series acousticresonator on the second die, the single series acoustic resonator of thefirst filter on the second die being the second acoustic resonator, thefirst acoustic resonator being connected to the common node via thetransmission line and the second acoustic resonator, the second filterincluding both a plurality of series acoustic resonators and a pluralityof shunt acoustic resonators on the same second die, and the first dieand the second die being positioned on a substrate; and a radiofrequency amplifier die positioned on the substrate, the radio frequencyamplifier die including a radio frequency amplifier operatively coupledto the first filter.
 18. The multi-chip module of claim 17 wherein theradio frequency amplifier is a low noise amplifier.
 19. The multi-chipmodule of claim 18 wherein the radio frequency amplifier die furtherincludes a second low noise amplifier operatively coupled to the secondfilter.
 20. A wireless communication device comprising: a multiplexerincluding a first filter and a second filter coupled to the first filterat a common node, the first filter including a first acoustic resonatoron a first die and a second acoustic resonator on a second die, thefirst filter including a single series acoustic resonator on the seconddie, the single series acoustic resonator of the first filter on thesecond die being the second acoustic resonator, the first acousticresonator being electrically connected to the second acoustic resonatorvia a transmission line, the first acoustic resonator being electricallyconnected to the common node via the transmission line and the secondacoustic resonator, and the second filter including both a plurality ofseries acoustic resonators and a plurality of shunt acoustic resonatorson the same second die; an antenna operatively coupled to the commonnode; a radio frequency amplifier operatively coupled to the firstfilter, the radio frequency amplifier configured to amplify a radiofrequency signal; and a transceiver in communication with the radiofrequency amplifier.